


The Sensual Machine

by DesdemonaKaylose



Series: Lost Light Megarung Collection [4]
Category: The Transformers (IDW Generation One)
Genre: M/M, Non-Consensual Body Modification, Spike Modifications (Transformers), robot titties, softcore bimboification, this fic is as tender as it is genuinely weird
Language: English
Status: Completed
Published: 2020-05-03
Updated: 2020-05-03
Packaged: 2021-03-01 20:35:13
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 5,940
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23973103
Author URL: https://archiveofourown.org/users/DesdemonaKaylose/pseuds/DesdemonaKaylose
Summary: “No, I’m not fishing for compliments,” Megatron says, “I mean quite literally, aren’t you having a harder time fitting me now than last week?”My contribution to the2020 Kink Zine: Primus slowly reshapes his lover’s frame to be a perfect pleasure engine – Rung has no idea this is happening, and Megatron is just along for the ride.
Relationships: Megatron/Rung (Transformers)
Series: Lost Light Megarung Collection [4]
Series URL: https://archiveofourown.org/series/1648138
Comments: 31
Kudos: 155
Collections: Kinks in the Wires (A free 18+ Transformers weird kinks fanzine)





	The Sensual Machine

**Author's Note:**

> Four months, and so much accomplished in so little time! It's been such a delight meeting and getting to know all of our contributors, and now I'm very pleased to present my own entry to a legacy of horny, bizarre audacity. Make sure you check out the rest of the collection, for more wheels, wires, and robo-titties.

On the Lost Light, there is an amount of free personal time unprecedented in Megatron’s life. Even when he was the supreme authority of an army, there was less time for recreational indulgence than he now finds himself in possession of. He is, lately, learning how to make best use of it.

“Mmm,” Rung breathes, sliding down another thick measure farther on Megatron’s spike. “Oh, darling, you feel so _good_ …”

Megatron almost never comes first; he’s used to that, he even takes some satisfaction from it. He likes to see how much he can make someone else feel, when he deigns to take a partner to berth. That’s really where the pleasure of interface comes from for him—watching someone come undone, giving them as much as they can take. But he’s usually more present in the moment than _this._

He knows that he has a good set of equipment, to certain tastes. His spike is girthy, raised ovals of biolights glowing big and smooth down to the base, with a fat head that makes a certain kind of mech all but drool. He is aware of this. He is also aware that he’s not got anything on the proportions of pre-war modding enthusiasts, but Rung has always seemed perfectly delighted to use him, regardless.

Megatron, watching his spike slide into the spread wide lips of that stretched-out valve, has a moment of disorienting uncertainty. He can hear the pitiful whine of servos and actuators. He can _feel_ the way Rung is straining to take him, the tremble in Rung’s hip joints. A standard one-size-fits-all valve shouldn’t have this much trouble accommodating his girth. The plush squeeze is almost painful.

“Rung,” he says, slowly, “do you remember… that is to say, does my spike feel larger than usual? To you?”

Rung arches up, a shiver running up his spine. “You’re superbly well endowed, darling,” he says, after the shudder has run its course. His valve is clenching and stroking furiously, in a flurry of weak pulses.

The biolights that push into Rung’s valve are swollen. They’re definitely rounder and brighter than he remembers them being before.

“No, I’m not fishing for compliments,” Megatron says, “I mean quite literally, aren’t you having a harder time fitting me than last week—”

Another fat biolight sinks into the tight clench ( _Primus_ ), and is he being over-cautious or does it take _longer_ , by a millionth of a klik, for this light to disappear inside of Rung?

Rung grinds his hips, trying desperately to impale himself further, mouth falling open so that his auxiliary vents can pull in air through his intake. His valve lips are so stretched that his anterior node is almost rubbing the shaft as it pushes into him, the little light all pushed out from its housing and blinking furiously.

Rung is panting, pulling cool air in through his mouth, optics unfocused. As sweet and hot as Rung’s valve feels around him, Megatron can’t stop thinking about how he _knows_ it wasn’t this difficult last week, or the week before that—in fact, now that he allows his suspicions free run of his memory data, it seems as if it’s been _getting_ more difficult, with each rendezvous, just slowly enough not to be noticeable. It’s almost as if his body is urgently adjusting itself to meet Rung’s needs, not satisfied until it can overwhelm the smaller bot utterly and totally, until it can fill Rung to capacity.

Even now he can feel Rung’s overworked internals trying to rearrange themselves around the intrusion of spike.

“That’s it,” Rung breathes, working his hips in needy little circles, “that’s it… darling, will you give it to me, please?”

Megatron rides out a shudder of his own, and then he doesn’t think about anything in particular anymore, except how lovely Rung looks when he’s being dragged down by the hips into a brutal, deep pounding.

It slips out of mind, until a few days later, when Megatron finally identifies the slightly uncomfortable ache in his frame as a soreness growing behind his chestplate. In the privacy of Rung’s hab suite, frame still pinging as it cools, he pops his chest panels and finds, to his dismay, that the emergency fuel tanks that come with this frame type—his old, first, frame type—are plusher, more swollen… the liquid inside bounces when he opens the compartment, both breasts jiggling.

Through the semi opaque membrane he can see one tiny bubble of empty space in the glowing energon. His hand hesitating even as he reaches for them, Megatron moves his fingers to one of the unusually pert nozzles. The tip is poking out like he’s been playing with it over a long intimate session rather than just leaving it tucked back inside his chest compartment like it _always_ is.

When he strokes over it, his knees almost give out.

They’ve _never_ been this sensitive, but then, they’ve also never been hard like this for who knew how long, while he went about his normal day. He resists the urge to squeeze them, just to feel that deep lingering ache sharpen. He still doesn’t know what this is all about, or what set them off.

From the berth, Rung shifts lazily and onlines one bright optic. “Mm?” he says.

Forgetting until a moment too late to be self conscious about his exposed breasts, Megatron half turns to him.

“Oh,” Rung breathes, “Oh, Megatron, I didn’t know you had _those.”_

Megatron cups one of them tightly to his body, as if offering it some inadequate protection. It’s not that he thinks Rung will react badly, it’s only—they aren’t supposed to be this _big_ , or this _sensitive_ , and he feels more exposed than he ever has, uncertain and vulnerable.

Rung sits up and hold out his arms. “Come here now,” he coaxes, “let me see them, won’t you? I’ll be gentle, I promise.”

After a moment, Megatron sidles up to the berth and lets Rung draw him in. Rung cups one breast delicately, stroking the curve of it with an absent thumb. A little shiver rattles the plating down Megatron’s back. The bubble inside the glowing liquid wobbles and races towards the highest point when Rung gives the whole breast a little push and squeeze.

“These are beautiful,” Rung murmurs, brushing his lips against the inner curve of the one in his hand. “This is my favorite frame type, did you know? It’s such a warm thing to feed a friend, so intimate…”

Megatron presses forward into the gentle grip, and Rung lets out a noise that can’t be called anything but _hungry._ He buries his face in the soft cleavage and squeezes hard, forcing a bead of energon to well up on the nozzle tip. It aches just like Megatron imagined it would, strut-deep, almost too good to bear.

“I hardly ever see this frame type anymore,” Rung sighs. “Ever since the refineries started being built in every city, there hasn’t been much need for fuel processor frames. I suppose underground was the last place it was still needed…”

He runs a hand up the angle of Megatron’s hip, up the small of his back and down again, splayed fingers ghosting over seams.

“They’re not usually this obtrusive,” Megatron admits. “The fuel mix you all have me on here must be kicking the refinery mechanisms into overdrive. I feel…” He grimaces, hyper aware of the unusual ache not just in his sore breasts but in his well-used and yet insatiate array. “…I feel overfull.”

Rung bites his lip. “Surely you don’t want them _smaller,”_ he says, like it pains him to even suggest. He pets the nozzle as if soothing it, making soft little circles with the pad of his thumb.

Megatron scoffs. “If they get any bigger, I’m afraid won’t be able to close my chest plate.”

Perched on his knees there, Rung makes a wanton sound, hips rocking up. Megatron lifts an incredulous brow ridge.

“Sorry,” Rung says, laughing a little and flustered. “I know it would be terribly inconvenient for you, in practice. It’s only that—well, you’d look so beautiful like that.”

Beautiful? Megatron? He’s been called handsome a few times by devotees who liked his rugged looks; words like _formidable_ and _brutish_ and if you’re feeling more complimentary, perhaps _charismatic_. But to be thought beautiful is new, and strange.

Rung catches the incredulous look on his face and hurries to clarify: “There would be a kind of perfection about it, you see? These are meant to care for your friends and comrades in dire times, and to see you so full that you’re spilling out of your chassis, it’s…” He thumbs the soft curve. “It’s vulnerable, yes, but there’s a power in it.”

Megatron doesn’t know what to say. The hand stroking up his back, the hand cupping his breast –the way Rung touches him, even before this particular revelation, is always so appreciative. It’s as if his nimble fingers seek out a tenderness under the plating that Megatron long thought stripped out of himself.

There were times in the darkness of his earliest life, before he was wise to the engineered cruelty of his own existence, when they would all touch each other like this. Clumsy work-worn hands feeling out the edges of a berthmate, sometimes too tired to do any more than lazily grind against tangled legs. And then when he’d left the dark for the last time, Terminus and all the rest behind him, he’d thought that softness lost to him forever.

Rung nuzzles closer, his cheek scraping over a tender nozzle.

“I feel as if you’ll take care of me,” Rung murmurs. “You _will_ take care of me, won’t you, darling?”

Rung wriggles down against the berth, knees falling open, his valve still slick and slippery from the last round. When he spreads his legs like that, Megatron can see just how much his own spike has hollowed Rung’s little valve out, forcing back the calipers until they can only weakly ripple with interest. Again he thinks: am I _really_ that big?

“You’re still revved up,” Megatron observes. “Didn’t I do a good enough job on you earlier?”

Rung wraps his hand loosely around his spike and pumps the shaft, inviting and available. “You did beautifully,” he says, “but I can’t imagine I’ll ever have enough of you looking like this.”

Megatron catches one knee and pushes it back, exposing more of Rung’s throbbing, swollen array. Rung hums, reaching up to brush his fingertips over the peak of a nozzle.

“Will you leave them out,” Rung asks, “when you fuck me?”

Megatron hesitates—but then, how can he resist Rung’s innocent hunger?

Megatron ends up bent over Rung at the edge of the berth, fucking him hard and sharp while Rung’s voice hitches and pops. The smaller mech is watching the heavy roundness of Megatron’s fuel refineries, the way they bounce with each thrust, liquid rippling inside. His optics are full of naked admiration, simmering lust. When he lifts a hand to squeeze one soft globe, Megatron groans and burns with unfamiliar embarrassment.

This is the sexiest he’s ever felt, and it’s enough to finally distract him from the niggling sensation that something here is amiss.

Over the course of the next few weeks, Megatron finds it more and more difficult to function as normal. The soreness in his chest isn’t fading, and as if that wasn’t distracting enough, there’s a low ember arousal situated firmly between his hips that only seems to be getting more persistent. 

At odd times—walking down the halls, getting rations, innocuous moments—he’ll be overcome by a warmth and need so powerful that he ends up leaning against walls to gather himself up again. It’s something about the walking, he thinks; it only happens when he’s been walking for a while, or sometimes when he crosses his legs in the captain’s chair…

Suspicion creeps up over him, itching at his back, but he can’t bring himself to check in his own hab suite which he effectively shares with Ravage. That would be one indignity too far. Eventually he resorts to borrowing a hand-mirror from Ultra Magnus’s contraband supply and pushing a rec room chair up against the inside door of the washracks, hoping that the clatter will be enough to warn him if some other crew member barges in. Privacy is in short supply on the Lost Light.

In an obscure corner of the room, a little foggy with steam, Megatron pulls his knees up against his chassis and opens his interface array. His valve gives a significant throb. He tugs one valve lip aside, revealing the red glowing bud of his anterior node.

It’s swollen, pushed out of its hood, bigger than he can ever remember seeing it. His hesitant fingers find it sensitive to the touch; even the softest stroke is like melting gold down his spinal strut.

He snatches his hand back and shivers. Even without his valve spread open, the tip of his node peeks out from between the curves of mesh. His modesty panel fits close over his valve lips, which isn’t normally a problem—but with the mesh all plump like this and then squished into tight confinement, the already-swollen bead of a sensory node pokes up, shifting when his hips open and close. Poking out far enough, he thinks, that it’s been rubbing little by little against the inside of his panel while he goes about his life.

He bites his lip and tries to push it back into place with the tip of a finger, receiving nothing for his trouble but a hot shot of pleasure-pain straight through his valve channel. He hisses. The mirror drops forgotten at his side.

Oh. Oh _damn._ Every soft bit of him sits up and begs for fingers and tongues like a starving hopeful mechanimal.

His chest plate transforms aside. His spike housing irises open. His helm hits the back of the shower wall, as he tries to get an intake of air that isn’t humid hot. This is, unsurprisingly, a lost cause. Everything about him feels overfull and overstimulated.

He needs—he needs—he needs a second opinion, that’s what he needs, that’s what…

He shoots Rung a brief message, relaying his location and a request for discretion, while his fingertips push at the edges of his valve. He doesn’t know what to do to make himself normal again. For someone who always has at least three alternate routes planned in advance, the sheer uncertainty is disorienting. This ship must be some kind of cosmic Tartarus designed specifically to punish him for his hubris.

He tries to sharpen up when he hears the clatter of the chair being pushed aside, but he lags a moment behind, not fast enough to close up his various panels. Rung stops dead in the middle of the floor, a first aid case in his hand.

 _“Oh,”_ he says. “Oh, this is not what I thought the issue was going to be.”

Megatron realizes a second too late that his left hand has started pinching and rolling the lip of his valve, unable to stop even as Rung takes in the whole picture on him there on the floor. He tries to stop, but he can’t bring himself to let go. Now that Rung is in the room, his whole frame yearns for the mech.

Rung sets down the case on the tile, and then comes warily across the floor.

“What’s the matter?” Rung asks. It makes sense to be wary, Megatron will admit, with someone who is so much larger and known for violence, especially when that someone might be wounded and disoriented. But he wishes Rung would forget those very reasonable fears and just touch him, grab him, anywhere, everywhere.

“It’s fine,” Megatron says, shortly. “I’m not hurt. I’m just—”

He scowls, at a loss for how to qualify the situation. His spike gives a meaningful throb.

Rung considers him silently for a moment, and then pulls off his glasses, kneeling neatly between Megatron’s open legs.

“Where’s the problem, darling?” he says. His fingertips light on Megatron’s breast. “Is it here? Are they bothering you again?”

“Well,” Megatron says, “yes. That is _one_ problem.”

Rung makes a sympathetic noise.

“I _am_ going to have to empty these out,” Megatron says, unhappily. “The production isn’t slacking off, and the pressure is absolutely maddening. But if it was only that, I could deal with it.”

Rung frowns. He looks up and down Megatron’s frame, tracing fingers down from his chest to his hips. “What else is it?”

“Rung, _look_ at me,” Megatron says, tilting a knee out, gesturing to himself. “My spike is so big I can hardly get it inside of you anymore. The fuel refineries won’t shut off. My node—”

He cuts himself off, as his gesturing accidentally bumps the back of his knuckles against his inescapably pressurizing spike. The biolights fit and fizzle; his spike gives a hard twitch.

Rung runs a soothing hand down the outside of Megatron’s thigh. Or it’s most likely _meant_ to be soothing. In actuality, it makes his valve start to drool on the tile. “What was that about your node?” Rung prompts him.

“See for yourself,” Megatron says, because at this point he can’t see much past the swell of his spike anyway.

Rung leans in, glancing up once to check for permission, before carefully pushing the spike up against Megatron’s belly. It immediately expands another measure thicker under the restraint of his fingers. There’s a soft _oh_ as he pushes away mesh to reveal the fullness of the bright red nub blinking up at him.

“That _is_ big,” Rung admits, “even for your frame proportions. It must be very sensitive.”

“You see what I mean?” Megatron asks. “I’m changing. I can’t explain why yet, but I’m being altered somehow.”

Rung tsks. “You’re just a little swollen,” he says. “There’s nothing wrong with having a big anterior node, Megatron. Personally, I find them delightful. Wonderful for sucking on…” he adds, giving the thigh a playful squeeze.

It feels _good_ , unfortunately. He can’t help but think how good it would feel to be squeezed somewhere a little more intimate, or—yes, Rung’s mouth, delicately suckling the fat bead of his node, tongue soothing the miserable little thing into euphoric relief.

“I’m not swollen,” Megatron retorts. “Not—not _just_ swollen, at any rate. I’m different than before, surely you can see that?”

“Mm. You hardly ever let me play with your valve,” Rung says, “I wouldn’t know. I think it’s just _lovely_ though. If you’re feeling worked up, you could let me ease things for you…?”

“I,” Megatron says, but then the sight of Rung’s thumbs opening him up, spreading his valve like delicate wings pinned open, sends a ripple of need through his circuits.

“ _The sensual machine_ , Sparklight once called the body,” Rung says, fingers petting Megatron’s wet valve lips. “It’s been a long time since you allowed yourself to be sensual, hasn’t it? You spent a long time hardening yourself, becoming unapproachable, an ideal… an emperor… these soft parts of you must seem unfamiliar.”

“Rung, these things are _different_ ,” Megatron says. “These are not supposed to be this way.”

Rung hooks two fingers inside the clutch of Megatron’s valve and strokes the back of where his anterior node is anchored, a place Megatron didn’t even know was sensitive until this very moment. “Shh,” Rung soothes. “In this new frame, with these old specs, it’s nothing to be ashamed of if you’re still relearning your body.”

“I’m not,” Megatron tries, “it’s not—”

The wretched poison they’re feeding him here must be sapping his will as well as his strength. When Rung runs his thumb through the beading fluid at the tip of Megatron’s spike, smearing it down over the sensitive head, all the words in the world fly out of Megatron’s processor. He becomes some needy thing he hardly recognizes, pushing up against Rung’s hands, making undignified noises, clutching his own breasts and squeezing them just to get a little more out of his overworked frame.

He has the hazy thought that _whatever_ this is, whatever is happening to him, its ultimate goal is to make him some hedonistic pleasure drone—some carnal creature unable to walk the halls without working himself into a shameless frenzy, turned on by anything and everything, luxuriously swollen and powerless to resist the offer of a good fucking. Will he go crawling to Rung, at the end of every shift, valve dribbling and spike hard, begging to be taken in hand?

The idea horrifies, and at the same time—at the same time, he flares so hot that he distantly wonders if his components have begun to melt. Wouldn’t it be good, after all this time, to surrender command of himself to someone else? To someone he can trust?

Megatron lets out a whine that hardly resembles any sound his voice has made before, desperately pinching and squeezing himself. The pistons in his knee fire randomly as Rung strokes him to overload—spike snug in the grip of his hand, relentlessly working it even through spurts of silvery fluid. 

When Rung has milked him dry, Megatron lets his helm roll against the wall so that his mouth puffs hot steam over the tile, dazed and unfocused.

“There we are,” Rung says. “Do you feel better, now?”

Megatron lets out a sound verging on a whimper. He doesn’t feel relief. Instead, the rest of his tender places only ache harder, like they all want nothing more than to be kneaded and worked over one inch at a time until he’s nothing but exposed nerve relays.

He tries to spread his thighs wider, pushing up against Rung’s fluid-splashed fingers. He wants Rung to touch him. Against the haze that everything else has become, that one need is stark and clear. He needs Rung to be pleased with him, to take him, to use him. He wants to be praised, to be good for the mech who takes such care of him.

Rung presses the flat of his palm against the dripping array, cupping it gently. “Oh, sweetspark,” he murmurs. “You’re in a bad way aren’t you?”

Megatron casts him a bleary sideways look.

“Shh, now,” Rung says, grinding the heel of his palm into Megatron’s enflamed node, “don’t worry, I have you. You’re so beautiful, darling, I’m so lucky to be able to touch you. We can take as long as you need, alright? I’ve let Ultra Magnus know the washrack on this floor is off limits for today while I’m assisting someone. No, don’t panic, I didn’t say who.”

Megatron subsides, worn out by the brief moment of clarity.

“You’re so beautiful,” Rung says again, reassuring him, while his fingers gently roll the poked-out nub. It almost _burns_ , it’s so intense—Megatron twitches as he fights to stay silent against the gentle assault.

“I love your body,” Rung tells him. “If it wasn’t so silly, I’d say you were made for me. But I doubt Shockwave had me in mind when he put you back together last.”

Based on past experience, Megatron doesn’t think Shockwave would have put _any_ thought into how pleasant or unpleasant this frame would be to live in. He had never concerned himself with it much before. And perhaps that’s why this is so disorienting, and so hard to resist. Somewhere along the way, Megatron forgot what it felt like to enjoy living inside of his body, rather than just bearing the strain and grind of it. He’d thought of his frame as a tool.

“I feel good,” he mumbles. “I didn’t even know I _could_ feel good, anymore.”

Rung lifts one hand and cups it around Megatron’s cheek. He leans into it, optics dimming.

“And?” Rung says. “Do you like it?”

All the ache and the yearning; all the cascading pleasure, the sweet burn; in his other lifetime he would have subsumed it all into the iron grip of his processor and let it die there. Rung knows him well enough to know that he’s never really been comfortable with simply _feeling_.

But he looks down at his frame now, the frame that Rung seems so delighted with—the frame that Rung kisses and fondles, as if it deserves an ounce of gentleness—and imagines the simplicity of existing only to feel good, and to make someone else feel good.

“Yes,” he admits, “I do like it.”

Bonus:

Two days later, he’s on the bridge, rubbing absently at his chest plate, more sore than ever, when Rodimus leans over his station.

“You okay there bud?” the mech says, in an amused undertone.

Megatron glances up. Rodimus shoots a meaningful look at his chest. Megatron stiffens.

“I know that fidget,” Rodimus says. His optics do some meaningful flashing and widening, completely without subtlety. “I’ve been there, man. Yours just coming in or something?”

“I have no idea what you’re talking about,” Megatron says.

Rodimus leans in a little closer, probably the closest he’s ever willingly gotten to the mech who once shot him. “You got fuel refineries under there, right? I got a set when the Matrix upgraded me.”

“You have a set?” Megatron repeats.

Rodimus winks. “And some other perks. Seriously though, you need to take a break?”

Megatron’s need to show himself as the more responsible co-captain wars with his need to _not_ continue discussing this on the bridge in full earshot of Blaster, who has excellent audio pickup. He is not confident in his ability to make Rodimus stop talking about this. Escape is the more reliable option.

“Fine,” he says, heaving himself up out of the chair. “You can take command while I’m gone.”

Rodimus makes a face. “It’s not my shift,” he says. “I’ve got plans.”

Megatron digs the heel of his hand into the corner of his chest plate. “Well then why did you suggest _I_ take a break?”

“Cause you need one, Captain Gloomsday,” Rodimus says, and promptly takes him by the elbow. “Ultra Magnus has it covered, don’t you Magnus?”

Megatron—who had not previously considered that Ultra Magnus might be listening—takes one second to meet their SIC’s guilty gaze, realizes his error, and then allows himself to be reeled out into the corridor to avoid further disrupting the pleasant work environment to which they were accustomed with overly personal interaction.

Rodimus pulls him along, down the hall, and way from the bridge.

“How dare you embarrass me in front of the command staff like that,” Megatron says, in a heated undertone.

“Oh yeah, sure, you wanna just keep feeling up your titties in front of Primus and everyone, you go right back in and do that,” Rodimus says, shooting him a scorching glare. “I don’t know _why_ I expected you to be grateful about anything I do, you’ve made it _real_ clear you think I’m not fit to scrub a waste disposal tank. Well next time I’ll just let you work it out on your own, huh?”

Megatron presses his lips together and does not say the thing that is sitting on the tip of his tongue. He is _trying_ to be better about not letting his… coworkers… bait him into losing his temper. Especially since the more time he spends with Rodimus, the more he realizes that Rodimus _isn’t_ baiting him, actually. He’s just like that, all the time, with everyone.

“I appreciate that your concern is… genuine,” Megatron says, stiffly.

Rodimus makes a scoffing noise.

“I would have preferred for no one to notice,” Megatron says. “Genuine concern or not. It’s a private situation. I’m dealing with it.”

“Uhuh,” Rodimus says. “Kinda looks like you _haven’t_ been dealing with it.”

Megatron turns his head to scowl at Rodimus, but finds Rodimus too busy considering the chestplates in question to notice. “It’s private,” he says, again.

“Yeah. And how’re you gonna get those bad boys under control, _privately?”_

Megatron hesitates. “I don’t see how that’s any of your business.”

Rodimus shrugs. “Like I said, I’ve been there. Looking at you is giving me sympathy aches.”

Megatron presses a hand to his chest again, and only notices it a moment too late to hide the gesture.

“When I first got mine you’d just shot me,” Rodimus says, “so at first I thought it was just self repair aches. But then it got so bad I had to pop the plates to make sure I hadn’t started growing rust, and bam! There they were, like a couple of water balloons. So I got back to base and I had Ratchet give ‘em a look, and he said the same thing I bet he’s gonna tell you, which is—”

“Matrix exposure,” Ratchet says, shoving his hands into a bowl of anti-rust decontaminant. “Damned if I know how the stupid thing works, but it’s got an effect on people you can measure with tape.”

Megatron, on the medical berth with his chest plates open, scowls at Ratchet.

“I’ve never shown any of the so called signs of matrix affinity,” he says. “Such a thing is autobot superstition, anyway. All this wishful nonsense about blue optics and smelling metal—”

“Well I don’t know about any of that slag,” Ratchet says, shaking out his hands, “but it sounds like you’ve got one of the worst cases of matrix exposure I’ve ever seen, and I’ve been a doctor for every Prime since the silver age. Pop your codpiece.”

Refusing to be embarrassed by basic medical procedure, Megatron shifts open his modesty panel and looked at the wall.

“Yeah, see, you’ve got the same problem most Primes I’ve treated have—the spike housing is all stretched out to make room for the new growth in the spike shaft, you can see where the new metal in the stretch marks is shinier. And your anterior node is definitely oversized for its housing, it can’t even fit back inside when it’s unaroused.”

“Ridiculous,” Megatron says. “These are not signs of affinity, and even if they were, why would I be having them now?”

“No, this is more like the other end of the process,” Ratchet says. “So you tell _me_. What’ve you been _doing_ to get this kind of reaction, sticking your arm in Rodimus’ chest?”

“Certainly not,” Megatron says.

“Hmph. We lost our half of the matrix on Luna 1,” Ratchet says, “so—(I’m going to spread this, hold still) so it can’t be from _that,_ and Rodimus is the only other thing on the ship with any relevance to the matrix (this is going to be cold, hang on) so I’m stumped if I know where it’s coming from, if it’s not from _him_.”

Megatron winces as Ratchet pulls the speculum out of him. His treacherous valve is waking up, apparently interested in the novel experience of being mercilessly prodded with something hard and cold.

“These are standard exposure side effects,” Ratchet says, “the enlargement, the refinery growth—although you actually had those to begin with, so your growth is more accelerated—increased lubricant production—I expect we’re going to find even the chemical composition of the interface fluids is altered—honestly it’s matrix one-oh-one with these symptoms.”

Pink lubricant starts to dribble out of the cleft of Megatron’s valve. Ratchet glances down, and then does a double take. “If I didn’t know any better, I’d say you’d been licking the damn thing,” he says.

Megatron resists the urge to cross his legs.

“Ask him who he’s been fragging!” comes a shout from the other side of the examination room door.

“Rodimus!” Ratchet barks, “If you can’t keep your nose out of it, I’m banning you from the med bay for good!”

“You can’t do that!” Rodimus shouts back. “I’m his co-captain! If weird sex magic is happening on this ship, I deserve to know about it!”

Ratchet sighs through his nose. “I really will ban him, if you want,” he offers, which is possibly the most sympathetic towards Megatron he’s ever been.

Megatron considers it. “No,” he says, “he already knows too much, he’ll only be more trouble for me if he thinks you’ve left him in the dark.”

“Ask him!” Rodimus shouts again, and thumps the wall for emphasis.

Ratchet rolls his eyes. “Who _have_ you been intimate with in the last year, if anyone?”

“Is it Optimus?” Rodimus shouts. “If it’s Optimus you have to tell me! I have 2 k riding on this!”

Megatron reconsiders letting Ratchet ban him.

“I’ve only interfaced with one person in several centuries,” Megatron says, “and he is certainly not a Prime.”

Ratchet rotates a finger impatiently. “And that would be…?”

“Rung,” Megatron says.

Ratchet blinks, once, but otherwise his face betrays nothing.

“RUNG???” the voice outside the door bellows.

Megatron raises his hands up to his face and digs the heels of his palms into his optics.

“You’re fragging _Rung?_ Are you on a mission to have the most boring sex in the galaxy or something??”

Megatron tilts his helm back. “You really shouldn’t speak about things you don’t know,” he says, through his hands.

“Don’t get me wrong, I love Rung, but—hey, are you telling me you’re using _that_ spike on Rung?”

Megatron sighs deeply.

“ _Our_ Rung? That thing’s gotta be as big as his entire thigh! I mean if it’s anything like mine, which I assume it is, how are you not splitting him in _half?”_

Megatron’s mouth twitches against a smile. He lowers his hands to the bottom of his face to hide it. “Apparently by sheer coincidence I’ve become equipped with exactly what he likes.”

There’s a moment of silence. Then Rodimus says, “I’m comming Swerve. They’re playing party games at the bar, it’s Truth or Shot night. Rung’s a teetotaler; he’ll have to answer if the alternative is drinking.”

“Do _not_ force him to reveal our relationship,” Megatron orders, modesty panel snapping smartly shut. “Even if you don’t respect my wishes, you _must_ understand how it could impact his relationship with the crew, should it become common knowledge.”

“Relax!” Rodimus says, “I’m just asking about his dick preferences!”

 _“Why?”_ Megatron says, already despairing of the answer.

(In the bar, Rung gently slides a shotglass full of something bubbling away from himself, and says, “All other things being equal, I admit I’m a bit of a size queen. Since you asked.”)

“Look, forget about all that,” Ratchet says, waving the whole ridiculous conversation off. “If we don’t know where the exposure is coming from, we can’t stop it. So here’s what you have to look forward to: increased lubricant viscosity, increased libido, enlarged labia, and overall frame sensitivity. It’s not dangerous; any number of Primes have survived just fine with it. You’re going to need to have the refineries pumped every so often, though. It’s perfectly good fuel, your body would have already taken care of the impurities in the... rations. You can decide what to do with the final product.”

Megatron wrinkles his nose at his fuel sacks. It seems like something that most autobots would not welcome, and certainly not from him.

Ratchet, apparently following his train of thought, coughs and says, “Perhaps your… paramour.”

Megatron pauses, thinks about Rung pressed tight against him, seated in his lap. Thinks about the stroke and squeeze of delicate fingers, the gentle press of a tongue—Rung nosing against him, thanking him, kissing his nozzles, losing himself in the taste of fuel.

“Perhaps,” he says, slowly.

Another rush of hot, pink fluid dribbles out of him, secret and unseen.


End file.
